Hi from new PV homeowner

[Chrisbee]

Hello, new here (obviously).
I've recently had a PV system installed and wish to make the very most of it.

I'm a retired broadcast systems engineer, so while not qualified for domestic electrics, I do like to understand everything in my home, down to the last detail.

My system is, I guess, fairly typical. Consisting of 4.5kw of panels, a Solis hybrid inverter and 4.8kwh of Pylontech battery backup.
Half of the panels are on a roof facing SW and half on a roof facing SE.

My first question will be about typical daily yield and peak power for this time of year, in my location. (Stafford, Staffs, UK). Should this be in another thread?

 

[Murdoch]

TBH thats a really tricky question to answer as its rather dependent on the weather. e.g. our panels produced the most in April last year.

I too have a Solis inverter - do you have the Wifi option on it?

This:

https://www.solenenergy.com/solar-1/inverters/solis-data-logging-stick-wifi-sol--dls--w
To be recommended!

 

[Chrisbee]

Hi Murdoch, thanks for replying.

Yes I do have the WiFi option and seem to be poring over graphs and stats every day.
In the last day or so of this rapidly changing weather, I've hit a peak that matches the installed capacity of 4.55kwp, but only very briefly.
Prior to that there have been days in March with no or very little cloud all day where peak power was only 3kw or so.
I had assumed that this was because my roofs are at 90deg to each other so I'll never see the sun straight on to the whole system at any time of day.

Or maybe simply because it was "only March"?
Some days yield has been over 20kwh.

I'm very pleased with performance so far. Just hoping that's justified?

 

[Murdoch]

Have you got a hot water tank with an immersion ?

 

[Chrisbee]

I do, with a Solic200 diverter too. Although that doesn't kick in until mid afternoon after the battery is full but I need hot water earlier in the day.

I'm also wondering how relevant the diverter is considering the SEG rate I'll be getting for exporting electricity is pretty much the same per kWh as the cost of gas per kWh to heat water anyway?

 

[Murdoch]

TBH it sounds like you have the ideal set up so do nothing except monitor your gas and lecky consumption each month.

re your water, surely the hot water from the previous day should still be in the tank in the morning ?

winter months can generate very little solar power ….

 

[Chrisbee]

Thanks again.

Yep, monitoring gas, electric and hot water temp has revealed a decent saving I can make. (But haven't yet sorted).
I have a hot water loop and circulating pump. Because we're in a large bungalow with a granny annexe and some hot water taps are a long way from the tank, the loop means hot water is available very quickly at every tap and we waste very little water.

The cost of running the pump is trivial but what I have found is that the loop of pipe is so long, convoluted, and in places poorly insulated, that I'm losing temperature quite quickly through that.

Switch it off and temperature holds as you say. But then I get complaints of how long hot takes to come through.

You've also confirmed it should hold temperature a lot longer too, thanks.
So I'll be shortening the loop and making sure it's much better insulated. I'll be adding a timer so it's off at least overnight too.

So do you think my 20kwh on a sunny March day is OK?
I recon my two roofs might give me a lower peak power than a single roof, but it's spread out longer through the day.

 

[Murdoch]

Pumping hot water around your hot taps when not needed sounds a waste of money to me …..

 

[Chrisbee]

It does on the face of it, but it's a well known technique even if it is a bit of a luxury. There are articles on the www showing the pros and cons. Some even say they can save money.

The alternative is a long wait for hot water, along with the waste of water and waste of heat in the pipes after switching off. I did get strong complaints from family when I recently switched it off for a week.

I'm considering a switch to a shorter loop that's just above the ceiling only. Very well lagged and also buried in loft insulation. Timed to only run during peak use periods. Maybe manually activated or by PIRs in bathrooms.

Room for improvement for sure.

 

[binky]

hot water loops are energy wasting planet detroyers! You would be better off with local electric water heaters.

So, your PV has turned you into a weather watcher - you'll get over that eventually
You will rarely see a 4,5 kWpeak from a split system, but the fact you have shows it's all working well. Best months for output are usually May /June when the days are long and air is cleaner. It's very hard to give figures for a particular time of year. If you look on line there's loads of public data available from installed system, the SMA portal link below lits 1500 UK system you can peruse and compare your with - ideally find a similar system to yours near Stafford https://www.sunnyportal.com/Templat...=9fdac350-8133-4b4c-bdfd-bacc8325d390&splang=

 

[Chrisbee]

Thanks binky, yeah that's what my recent tests are beginning to show too, sadly. Changes will be made one way or another.

Many thanks for the link, I hadn't found anything like that.